This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Voltage-gated potassium (Kv) channels (http://www.ks.uiuc.edu/Research/kvchannel/) are integral membrane proteins present in all three domains of life. In a specialized class of animal cell, known as excitable cells - including neurons, muscle cells, and endocrine cells - Kv channels work with other cation channels (sodium and calcium channels) to regulate the electrical activity and signaling of the cell [1]. Kv channels activate (open and close) in response to changes in the electrical potential across the cell membrane allowing passive and selective conduction of K+ ions through the channel. Potassium conduction is directed by the electrochemical gradient across the cell membrane and can achieve very high rates, while still discriminating against all other cations (including the smaller Na+ ions) [1]. In addition to electrical signaling in nervous systems, Kv channels play an important role in the regulation of cardiac excitability and regulation of insulin release. In humans, malfunction of these channels can result in neurological or cardiovascular diseases such as long QT syndrome or episodic ataxia [2].